Browsing by Author "Zeidan, Hani"

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Adsorptive Separation of Propionic Acid From Aqueous Medium Using Efficient Anion Exchange Resins in Batch and Fixed Bed Column Systems
(Wiley, 2025) Marti, Mustafa Esen; Isik, Murat; Zeidan, Hani
The recovery of propionic acid (PA) from aqueous medium using a strongly basic, Lewatit M-600 (LM-600), and a weakly basic, Lewatit MP-62 (LMP-62), anion exchanger was investigated. Medium conditions such as pH, temperature, PA concentration, and resin dose affected the performance of the process. The highest capacities were achieved at pH 5 and 2 with LM-600 and LMP-62, respectively. Equilibrium was reached in 35 min, and the process followed the pseudo-second-order kinetics for both anion exchangers. LMP-62 was more effective at pH values lower than 5. The exothermic process was found to be spontaneous. The maximum capacities of the strong and weak basic exchangers in batch experiments were 135.7 and 363 mg/g, respectively. However, the breakthrough capacities obtained in fixed bed systems were lower than those attained in batch systems (94.75 and 123.73 mg/g for LM-600 and LMP-62, respectively), and the column was successfully regenerated using 0.6 M NaOH. The Freundlich isotherm model yielded the highest determination coefficients in the isotherm analysis, suggesting that physical forces between PA and resins primarily drive the process.
Coprecipitation Method for Preparing Cobalt Oxide (Co3O4) Catalyst to Efficiently Oxidize Ammonia
(Pleiades Publishing Ltd, 2025) Al-Okla, Mudar; Zeidan, Hani
In this study three samples of cobalt oxide were prepared via coprecipitation at pH 9.5 using cobalt nitrate as a precursor. They were dried at 120 degrees C before calcining at 400, 500, and 600 degrees C. The crystalline phases were determined using X-ray diffraction (XRD), revealing the presence of the Co3O4 phase in all prepared samples in varying proportions. Fourier Transform Infrared Spectroscopy (FTIR) spectra showed distinct bands corresponding to the vibrational motion of the Co-O bond, confirming the formation of cobalt oxide (Co3O4). Scanning electron microscope (SEM) analysis of the Co 500 sample revealed particles in the range of 40-350 nm (average similar to 100 nm) with relatively low agglomeration, while energy-dispersive X-ray spectroscopy (EDX) confirmed a composition consistent with stoichiometric Co3O4 (85.7 wt % Co and 13.6 wt % O). Pyridine-adsorbed FTIR spectra indicated that the sample calcined at 500 degrees C possessed the most balanced ratio of Lewis and Br empty set nsted acid sites, which correlated with its highest catalytic activity. The textural properties of all samples were analyzed using nitrogen adsorption data at 77 K, and the adsorption isotherms were found to be type IV, with hysteresis loops indicating capillary condensation in mesopores. The specific surface area reached a maximum of 4.837 m(2)/g for the sample calcined at 500 degrees C. This sample also exhibited the highest total acidity (0.035 mmol/g) and strong acidic sites (the initial electrode potential value E-i = 73.2 mV), which enhanced catalytic performance. Pore radius calculations further revealed that the samples contained mesopores. The catalytic efficiency of the prepared samples in the ammonia oxidation reaction was evaluated at 450 degrees C. The sample calcined at 500 degrees C demonstrated the highest catalytic activity. The sample calcined at 500 degrees C achieved 100% NH3 conversion at 475 degrees C and maintained full activity over 10 consecutive cycles, demonstrating high stability and reusability.
Citation - WoS: 5
Citation - Scopus: 5
Effective Isolation of Succinic Acid From Aqueous Media With the Use of Anion Exchange Resins
(Royal Soc Chemistry, 2024) Asım, Hamayoun; Zeidan, Hani; Marti, Mustafa Esen
The primary objective of this study was to examine the isolation of succinic acid (SA) from aqueous-based solutions through the utilization of adsorption and ion exchange methods. Four kinds of anion exchange resins were employed, two of which were strong basic (Lewatit M-500 and Lewatit M-600), and the other two were weak basic (Lewatit MP-64 and Lewatit MP-62). The impacts of various variables on the efficiency of the process were examined. The aqueous pH strongly influenced the separation yield. Weak basic exchangers achieved the maximum yield at pH 2.1. However, the highest performance with Lewatit M-600 and Lewatit M-500 was obtained at pH 5 and 6, respectively. The SA separation with the tested resins reached equilibrium in about an hour. The recovery data revealed consistency with the Langmuir isotherm and pseudo-second-order kinetics. Efficiency improved with resin dosage and reduced with SA concentration. It was found that weak basic anion exchange resins were more efficient than strong basic exchangers for the recovery process. Among the resins tested, Lewatit MP-62 demonstrated the highest sorption capacity of 321 mg g-1 and 97.5% yield. The performance of the system decreased with temperature for all alternatives tested; however, its impact was not notable. The isolation process had an exergonic, exothermic, and favorable character based on the thermodynamic constants. Acid-loaded resins were successfully regenerated using trimethylamine and HCl for weak and strong anion exchange resins, respectively. Succinic acid recovery using weak basic anion (WBA) and strong basic anion (SBA) exchange resins.
Citation - WoS: 10
Citation - Scopus: 10
Efficient Recovery of Itaconic Acid Using Weak and Strong Anion Exchange Resins From Aqueous Solutions
(Amer Chemical Soc, 2024) Can, Cihat Erdem; Zeidan, Hani; Martı, Mustafa Esen
Itaconic acid (IA) has the potential to be one of the industry's most remarkable raw materials, but it must be recovered with high efficiency and selectivity from complex aqueous-based production media. In this study, three types of weak basic anion exchangers (WBAEs, Amberlite IRA-67, Lewatit MP-62, and Lewatit MP-64) and a strong basic anion exchanger (SBAE, Lewatit M-500) were tested for the separation of IA from aqueous solutions. The process was considerably affected by the operating pH, and the highest efficiencies were obtained at pH 3 and 4 with the WBAEs and SBAE, respectively. Equilibration was achieved in similar to 60 min, and the data fitted the pseudo-second-order kinetic model for all resins tested. Decreasing yields with an increase in temperature confirmed the exothermic nature of the process. Isotherm curves demonstrated the consistency of the equilibrium data with Type I. The capacities increased with IA concentrations and decreased with resin doses. Lewatit MP-62 achieved the highest capacity (522.7 mg of IA/g of resin), and its performance was significantly better than those previously reported in the literature. The equilibrium data were in agreement with the Langmuir isotherm model; however, the R 2 values attained with the Freundlich and Temkin models were also relatively high, indicating the need for further isotherm analyses.
Citation - WoS: 9
Citation - Scopus: 9
Evaluation of Olive Pomace for the Separation of Anionic Dyes From Aqueous Solutions: Kinetic, Thermodynamic, and Isotherm Studies
(DESALINATION PUBL, 2021) Ali, Khalid; Zeidan, Hani; Martı, Mustafa Esen
Today, water pollution is one of the major problems threatening human health. Synthetic dyes from industrial effluents are among the many toxic compounds that cause water pollution. The aim of this study is the evaluation of olive pomace (OP) to be used as a biosorbent during the separation of two anionic dyes, Congo Red (CR) and Methyl Orange (MO), from aqueous solutions by adsorption technique. The biosorbent was characterized using Fourier transform infrared, Brunauer-Emmett-Teller, Barrett-Joyner-Halenda, and scanning electron microscopy with energy-dispersive X-ray spectroscopy. It was shown to be largely unaffected by pH, indicating that OP can be utilized over a wide pH range. Experiments were conducted without pH adjustment of aqueous solutions. Kinetics showed that adsorption followed the pseudo-second-order kinetic model and reached equilibrium in 210 min. Efficiency reduced with the increase in temperature and thermodynamic parameters indicated that physical or physico-chemical interactions may have occurred between the dyes and OP. The process was exothermic and non-spontaneous. The efficiency was negatively influenced by initial dye concentration while positively affected by the OP dose. The trend was reversed for adsorption capacity, resulting in maximum values of 145.0 and 257.4 mg/g for CR and MO, respectively. These were higher than those reported in the literature for the sorption of these dyes using various types of waste materials. The process was well-explained by Freundlich isotherm for both dyes. The OP was found to be effective for the separation of anionic dyes from aqueous solutions over wide pH and concentration ranges.
Citation - Scopus: 1
Impact of Temperature on the Structural and Optical Properties of Silver Sulfide Films Prepared by Chemical Bath Deposition
(Pleiades Publishing Inc, 2024) Tukko, Muhammad Nor; Al-hajji, Muhammad Ali; Alasle, Sulyman; Al-Okla, Mudar; Zeidan, Hani
Transparent semiconducting silver sulfide (Ag2S) thin films were deposited by chemical bath deposition technique on glass substrates. The effect of different deposition temperatures (10, 20, and 30 degrees C) on the structural and optical properties of silver sulfide films was studied. The XRD spectra showed that the structure of the films was monoclinic and polycrystalline, and the predominant growth of crystals was at the plane (022). The intensity of the peaks increases with increasing preparation temperature, becoming narrower and clearer. The best-structured films with the least crystalline defects were that prepared at 30 degrees C. UV-VIS spectroscopic scanning showed that all films had a minimum transmittance and maximum absorbance at the ultraviolet field within the range 300-350 nm. The transmittance decreased and absorbance increased with increasing wavelength and temperature. The energy gap values changed within the range 2.105-2.242 eV, which clearly increased with increasing preparation temperature.
Preparation, Characterization, and Use of Trimethoxy[3-(Methylamino)Propyl]Silane Functionalized Sba-15 for Congo Red Adsorption
(Soc Chemists Technologists Madeconia, 2024) Can, Mukaddes; Albayati, Suzan; Zeidan, Hani; Marti, Mustafa Esen
Mesoporous materials have aAbroad range of applications in industry, and one of which is their potential use in adsorptive separations. This research investigates the use of a secondary aminefunctionalized SBA-15 for the separation of a diazo dye, Congo Red (CR), from aqueous solutions. The synthesized SBA-15 was modified with trimethoxy[3-(methylamino)propyl] silane by a post-grafting method. The produced material was characterized using X-ray diffraction, N2 physisorption, scanning electron microscopy, and transmission electron microscopy. The hexagonal mesostructure was preserved after functionalization; however, the specific surface area, pore diameter, and total pore volume of SBA- 15 silica decreased. The adsorption of the diazo dye reached equilibrium by 50 minutes, and the data followed pseudo-second-order kinetics. While the yield increased with rising dosage and temperature, it decreased with CR concentration. The maximum adsorption capacity of functionalized SBA-15 (F-SBA-15) for CR uptake was found to be 211.07 mg/g. Thermodynamic data and parameters indicated the potential combination of physical and chemical interactions occurring during the adsorption process. The separation was endothermic and non-spontaneous; the equilibrium data fitted to the Freundlich adsorption isotherm at all tested temperatures. This study demonstrates that the secondary amine-functionalized SBA- 15 can be used for the elimination of a toxic anionic diazo dye from aqueous solutions.
Citation - WoS: 9
Citation - Scopus: 9
Reactive Extraction of Betaine From Sugarbeet Processing Byproducts
(Amer Chemical Soc, 2023) Altinisik, Sinem; Zeidan, Hani; Yilmaz, M. Deniz; Marti, Mustafa E.
Betaine from natural sources is still preferred over its synthetic analogue in secondary industries. It is currently obtained by expensive separation means, which is one of the main reasons for its high cost. In this study, reactive extraction of betaine from sugarbeet industry byproducts, that is, molasses and vinasse, was investigated. Dinonylnaphthalenedisulfonic acid (DNNDSA) was used as the extraction agent, and the initial concentration of betaine in the aqueous solutions of byproducts was adjusted to 0.1 M. Although maximum efficiencies were obtained at unadjusted pH values (pH 6, 5, and 6 for aqueous betaine, molasses, and vinasse solutions, respectively), the effect of aqueous pH on betaine extraction was negligible in the range of 2-12. The possible reaction mechanisms between betaine and DNNDSA under acidic, neutral, and basic conditions were discussed. Increasing the extractant concentration significantly increased (especially in the range of 0.1-0.4 M) the yields, and temperature positively (but slightly) affected betaine extraction. The highest extraction efficiencies (similar to 71.5, 71, and 67.5% in a single step for aqueous betaine, vinasse, and molasses solutions, respectively) were obtained with toluene as an organic phase solvent, and it was followed by dimethyl phthalate, 1-octanol, or methyl isobutyl ketone, indicating that the efficiency increased with decreasing polarity. Recoveries from pure betaine solutions were higher (especially at higher pH values and [DNNDSA] < 0.5 M) than those from vinasse and molasses solutions, indicating the adverse influence of byproduct constituents; however, the lower yields were not due to sucrose. Stripping was affected by the type of organic phase solvent, and a significant amount (66-91% in single step) of betaine in the organic phase was transferred to the second aqueous phase using NaOH as the stripping agent. Reactive extraction has a great potential for use in betaine recovery due to its high efficiency, simplicity, low energy demand, and cost.
Recovering Levulinic Acid by Adsorption Using Efficient Basic Anion Exchangers
(Taylor & Francis inc, 2025) Altinsu, Yasemin Cemile; Zeidan, Hani; Marti, Mustafa Esen
Levulinic acid (LA) is a versatile compound used in biofuels, resins, etc., and its efficient recovery is required for its high value-added use. This study investigates the use of four anion exchange resins -Lewatit M-500 (a strong basic anion exchanger) and three weak basic anion exchangers (WBAEs), namely Amberlite IRA-67, Lewatit MP-62, and Lewatit MP-64- for LA recovery. The effects of pH, agitation time, LA concentration, resin dosage, and temperature on the adsorption efficiency were studied via batch experiments. Solution pH significantly influenced the yield. The highest efficiency was obtained at pH 2.1 for the WBAEs and pH 5 for Lewatit M-500. The kinetic data followed the pseudo-second-order model with R-2 >0.99. Increasing temperature slightly decreased the efficiency, with negative values for enthalpy (Delta H degrees) and Gibbs free energy (Delta G degrees), suggesting that the process was spontaneous and exothermic. The yield increased with resin dosage but decreased with higher initial LA concentrations. The highest adsorption capacity obtained from the four resins followed the order: Lewatit MP-62 (487.7 mg/g) > Amberlite IRA-67 (418.0 mg/g) > Lewatit MP-64 (371.6 mg/g) > Lewatit M-500 (278.7 mg/g). The successive adsorption-desorption trials using Lewatit MP-62 showed a slight decline (90% to 85%) in recovery efficiency over five cycles.
Citation - WoS: 4
Citation - Scopus: 4
The Relation Between Surface Acidity and Moo3:al2o3 Ratio on the Ternary Mixed Oxide for the Conversion of Propan-2
(Scientific And Technological Research Council Turkey, 2022) Zeidan, Hani; Erünal, Ebru; Marti, Mustafa Esen
In this study, ternary mixed oxide catalysts containing Al2O3-MoO3-MgO and Al2O3-MoO3-WO3 were prepared with a changing ratio of MoO3:Al2O3 between 0.05 and 20.00. All catalysts showed 100% selectivity towards propene during the conversion of propan-2-ol at temperatures between 220 and 400 degrees C. The catalysts prepared from WO3 possessed very strong acid sites, which cause higher catalytic activity than catalysts prepared from MgO. Besides, the ratio of MoO3:Al2O3 was found to be directly proportional to the conversion yield for all catalysts. XRD results show that whole MgO reacted with Al2O3 and MoO3 to form amorphous MgMoO4 and MgAl2O4 phases during catalyst preparation. Furthermore, WO3 reacted only with Al2O3 to form Al2(WO4)3 and WO3 phase was also detected in the final product. The higher surface acidity and catalytic activity of Al2O3-MoO3-WO3 catalyst referred to this WO3 phase within the structure.
Citation - WoS: 5
Citation - Scopus: 6
Removal of Congo Red From Aqueous Solutions by Adsorption Onto Illite Clay
(Desalination Publ, 2023) Altaie, Omar T. S.; Zeidan, Hani; Karakaya, Necati; Karakaya, Muazzez c.; Marti, Mustafa E.
Many synthetic dyes are toxic and must be removed from industrial effluents to prevent critical environmental and health problems. Adsorptive technologies are favored and several adsorbents have been tested for this purpose. Efficiency, economic suitability, and environmental compatibility are the most critical criteria in the selection of an adsorbent. The focus of the present study was the adsorption of Congo red (CR), an anionic diazo dye, from aqueous solutions using illite mineral. The Brunauer-Emmett-Teller surface area of the mineral tested in the study was 44.73 m2/g. Solution pH had a significant effect on the process, with the highest adsorption efficiency (AE) at pH 5.7. The process reached equilibrium after 2 h and the relevant data were in good agreement with the pseudo-second-order kinetic model. Adsorption efficiency decreased with temperature; the process was exothermic and non-spontaneous, according to thermodynamic data. The isotherm curves were fitted with Type I adsorption, and adsorption capacity increased with illite dosage but was negatively impacted by initial CR concentration. The highest adsorption capacity was 61.02 mg/g, and the equilibrium data were well described (R2 = 0.999) by the Langmuir isotherm model. This study demonstrates that illite mineral can be used for the remediation of the anionic diazo dye Congo red by adsorption.
Citation - WoS: 11
Citation - Scopus: 12
Selective and Efficient Separation of Levulinic, Acetic and Formic Acids From Multi-Acid Solutions by Adjusting Process Parameters
(Elsevier, 2023) Zeidan, Hani; Martı, Mustafa Esen
This investigation focuses on the recovery of levulinic-(LA), acetic-(AA) and formic acids (FA) from aqueous mixed-acid solutions by reactive extraction using tri-n-octylamine (TOA). Alcohols were found to be the most efficient solvents tested. Recoveries increased with shorter alcohol chain length and higher TOA concentrations. Yields decreased with pH and maximum efficiencies were obtained at the unadjusted pH (1.83) of the ternary -acid solutions for all acids; with LA, maximum selectivity occurred at pH 5. Higher TOA levels enhanced efficiency in mixtures but slightly reduced selectivity. For LA recovery, efficiency and selectivity using 0.5 M TOA in 1-hexanol were 92 % and 23.8 %, respectively. Co-extraction of AA ceased at consecutive extractions (from 2nd to 10th) and 93.6 % of LA was recovered with a selectivity of 98 % after ten subsequent steps. LA in the organic phase was stripped with an efficiency of-91 % with aqueous 1.0 M NaNO3. Selective extraction of AA and FA from binary-acid solutions was achieved at pH 5. The selectivity and separation factor decreased at higher TOA concentrations; however, 94.2 % of the AA was recovered with a selectivity of 93 % after seven successive extractions, followed by-93 % recovery by back extraction. The remaining FA (94.2 %) in the aqueous solution had a selectivity of-95 %. The data show that multi-stage reactive extraction can selectively separate LA, AA and FA from ternary-and binary-acid solutions.
Citation - WoS: 18
Citation - Scopus: 16
Separation of Formic Acid and Acetic Acid From Aqueous Solutions Using Sugar Beet Processing Fly Ash: Characterization, Kinetics, Isotherms and Thermodynamics
(DESALINATION PUBL, 2020) Zeidan, Hani; Özdemir, Damla; Köse, Nezahat; Pehlivan, Erol; Ahmetli, Gülnare; Martı, Mustafa Esen
The present study is on the use of sugar beet processing fly ash (SPFA) during the separation of acetic acid (AA) and formic acid (FA) from aqueous solutions by adsorption technique. Kinetic studies showed that the equilibration time was about 70 min for AA while 60 min for FA. The related data were observed to follow the pseudo-second-order kinetic model. Isotherm curves exhibited that the process was fitted with Type 1. The adsorption efficiency increased with the increase in SPFA dosage and decreased with the AA or FA concentration. Equilibrium data were in consistency with the Langmuir isotherm model for both solutes. The adsorption capacities and removal efficiencies obtained with FA were higher than those with AA. The maximum values were 7.00 and 5.60 mmol/g for FA and AA, respectively. These values were considerably higher than the ones previously reported for the adsorption of these acids using several types of synthetic resins and fly ashes. Temperature negatively influenced the process but the effect was not significant. Regardless of the acid type studied, the process was exothermic and spontaneous. The results showed that SPFA can be efficiently used in the separation of these carboxylic acids from aqueous solutions.
Citation - WoS: 28
Citation - Scopus: 29
Separation of Formic Acid From Aqueous Solutions Onto Anion Exchange Resins: Equilibrium, Kinetic, and Thermodynamic Data
(AMER CHEMICAL SOC, 2019) Zeidan, Hani; Martı, Mustafa Esen
Wastewaters containing organic compounds such as acids, ketones, phenols, and amines can cause critical environmental problems depending on their concentration and composition. Efficient and low-cost separation of these components may also bring their reuse in industry while cleaning the aqueous streams. Formic acid (FA) is an important raw material in industry and is widely seen in wastewaters. In this study, two different anion exchangers were compared for the separation of FA from aqueous solutions. Effects of process parameters and the mechanism were discussed. Kinetic, equilibrium, and thermodynamic studies were performed, and the data were interpreted using the relevant isotherm and kinetic models. The results showed that Lewatit MP-64 was more efficient than Amberlite IRA-96 in the range of the parameters studied. The maximum adsorption capacity obtained with Lewatit MP-64 (442.75 mg/g) was significantly higher than that were previously reported in the literature for FA separation. The data were well explained by the Langmuir isotherm model. However, relatively high R-2 values were obtained with Temkin and Freundlich isotherms. Therefore, further studies are ongoing to clarify the mechanism.
Citation - WoS: 6
Citation - Scopus: 6
Separation of Pimelic Acid Using Tri-N in Various Organic Solvents by Reactive Extraction: Equilibrium and Modeling
(Amer Chemical Soc, 2022) Zeidan, Hani; Yurdakul, Merve; Martı, Mustafa Esen
Separation of carboxylic acids from dilute aqueous solutions is a challenging problem, and reactive extraction has been examined as an attractive alternative for this process. This study aims to investigate the reactive extraction of pimelic acid (PA) using tri-n-octylamine (TOA) in 1-hexanol, 1-octanol, xylene, and n-hexane. The highest extraction efficiency (E (%)) and distribution coefficient (K-D) were obtained at pH 3, which is the unadjusted pH of the aqueous PA solution. Extractive efficiency varied inversely with temperature and initial PA concentration but increased with the increase in TOA amount. The highest E (%) and K-D values (98.5% and 67.2, respectively) were obtained with 1-hexanol at initial TOA and PA concentrations of 0.2700 and 0.0375 mol/kg, respectively. The process was modeled using multilinear regression, and the model closely correlated with experimental results for all organic solvents tested.
Synthesis of CeO2@SiO2 Nanocomposites for Adsorption of Cu(II) and Pb(II): Insights from Batch and Column Studies
(Springer, 2025) Zeidan, Hani; Erunal, Ebru; Marti, Mustafa Esen
CeO2@SiO2 nanocomposites were synthesized via rotary evaporation and co-precipitation for efficient removal of Cu(II) and Pb(II) from aqueous media. Among the tested compositions, CeSi-3 (CeO2:SiO2 = 1:0.5) exhibited the best performance, achieving maximum adsorption capacities of 160 mg/g for Pb(II) and 138 mg/g for Cu(II) at pH 6. Adsorption followed a pseudo-second-order kinetic model and fit the Langmuir isotherm. Desorption was successfully performed using both diluted HCl and 0.01 M EDTA. HCl achieved complete desorption of Pb(II) and 86% for Cu(II), while EDTA reached 97% for Pb(II) and 85% for Cu(II), with both maintaining the structural integrity of the adsorbent. Only a slight decrease in adsorption efficiency was observed after 10 regeneration cycles using HCl and after 3 cycles using EDTA, confirming the excellent reusability of the material. In fixed-bed column studies, CeSi-3 showed similar breakthrough capacities of around 60 mg/g for both metal ions, well-described by the Thomas model. These findings demonstrate that CeO2@SiO2 nanocomposites are efficient, reusable, and chemically stable adsorbents for sustainable water purification applications.
Citation - WoS: 16
Citation - Scopus: 18
Synthesis, Characterization, and Use of an Amine-Functionalized Mesoporous Silica Sba-15 for the Removal of Congo Red From Aqueous Media
(Springer, 2023) Zeidan, Hani; Can, Mukaddes; Marti, Mustafa Esen
In this study, SBA-15 was synthesized and functionalized with [3-(N,N-dimethylamino)-propyl] trimethoxysilane (AF-SBA-15) using a post-grafting method and evaluated for use in the removal of an anionic synthetic dye (Congo Red, CR) from aqueous media. The synthesized mesoporous materials were characterized by small-angle XRD, N-2 adsorption-desorption, FT-IR, and SEM techniques. The ordered hexagonal structure of pure SBA-15 and amine-functionalized SBA-15 (AF-SBA-15) was confirmed by small-angle XRD analysis; surface area, pore size, and pore diameter were determined by nitrogen adsorption-desorption analysis. Kinetics showed that the process reached equilibrium after 90 min; adsorption followed pseudo-second-order kinetic model. Maximum efficiency was obtained at the unadjusted pH (8.8) of the aqueous media, and the efficiency was negatively affected by CR concentration, but increased with dose and temperature. While pure SBA-15 could not adsorb CR, the highest adsorption capacity and efficiency obtained with AF-SBA-15 were calculated to be 186.41 mg/g and 95.3%, respectively. The data were successfully fitted to Langmuir adsorption isotherm (R-2 > 0.99), and consistently, thermodynamics signified possible physico-chemical interactions between CR and AF-SBA-15. The process was shown to be endothermic and non-spontaneous. The results show that amine-functionalized SBA-15 can be used to efficiently remove toxic anionic colorants from aqueous media. [GRAPHICS] .
Citation - WoS: 20
Citation - Scopus: 20
Using Eco-Friendly Alternatives for the Recovery of Pyruvic Acid by Reactive Extraction
(Elsevier, 2023) Martı, Mustafa Esen; Zeidan, Hani
Efficiency, cost and environmental impact are important parameters that must be addressed in the recovery and purification of pyruvic acid (PA) from fermentation media. In this study, twelve vegetable oils were evaluated with three extraction agents for the reactive extraction of PA. Recoveries with trioctylamine (TOA) were significantly higher than those with tributylphosphate (TBP) and trioctylmethylammonium chloride (TOMAC). The reactive extraction yields with vegetable oils were similar and comparable to that with 1-octanol; among the tested oils, the highest efficiencies were achieved with almond oil. Efficiencies increased with higher extractant amounts, but were negatively affected by higher pH and PA concentrations. Higher temperatures caused slight negative effects on yields. Loading ratios (z) showed that 1:1 PA:Ext complexes most probably occur with all extractants tested; moreover, 2:1 PA:TOA may form due to the z values > 1 with TOA. The PA was stripped and organic phase was regenerated after two consecutive back extraction steps using 2.5 M NaNO3. Organic phases could be re-used 5 times with only a 1-2% decline in efficiency. Based on the performance parameters evaluated and extraction yields obtained, vegetable oils have the potential for use as organic phase diluents during reactive extraction of PA.